1. Field of the Invention
The present invention relates to a material structure having positive polarity, and, in particular, to a material structure having positive polarity capable of providing a high energy density and suitable for use as a cathode of both primary and secondary batteries.
2. Description of the Prior Art
Conventionally, in a battery using a Chevrel phase compound as a cathode component, the Chevrel phase compound is used in the form of a compressed powder. The energy density of such a cathode is low, being approximately 160 Wh/kg. In Japanese Patent Laid-open No. 207576/1986 a method for compounding a thin film of a high energy density Chevrel phase compound is presented. According to this method a Chevrel phase compound dispersed in an organic solvent is applied to a substrate, and then subjected to sintering. However, there are drawbacks to this method; e.g. the degree of adhesion of the Chevrel phase compound to the substrate is not sufficient, the process is difficult to use industrially, and the energy density is not high enough, not exceeding 1,000 Wh/kg. Because of this, a material exhibiting positive polarity which can be industrially applicable and provides a good efficiency is desired.